[PATCH] D55192: [PowerPC] VSX register support for inline assembly

[Nemanja Ivanovic via Phabricator via llvm-commits]

nemanjai added inline comments.


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Comment at: clang/lib/Basic/Targets/PPC.cpp:416
+const TargetInfo::AddlRegName GCCAddlRegNames[] = {
+    {{"vs0"}, 0},   {{"vs1"}, 1},   {{"vs2"}, 2},   {{"vs3"}, 3}, 
+    {{"vs4"}, 4},   {{"vs5"}, 5},   {{"vs6"}, 6},   {{"vs7"}, 7},
----------------
ZhangKang wrote:
> ZhangKang wrote:
> > ZhangKang wrote:
> > > jsji wrote:
> > > > RegNum is wrong here!
> > > > "vs0" should be mapped to RegNum of "f0", which is 33. 
> > > > "vs32" should be mapped to RegNum of "v0", which is 78.
> > > I will learn it and check it, thanks for your point out my error.
> > Here, the value of `AddlRegName` is responding to the gcc macro `ADDITIONAL_REGISTER_NAMES`. In the array `ADDITIONAL_REGISTER_NAMES`, `vs0~vs31` should be mapped to RegNum of `f0~f31`, which is `32~63`. And `vs32~vs63` should be mapped to RegNum of `v0~v31`, which is `77~108`.
> Below is the  `ADDITIONAL_REGISTER_NAMES` GCC manual said:
> ```
> Macro: ADDITIONAL_REGISTER_NAMES
> 
>     If defined, a C initializer for an array of structures containing a name and a register number. This macro defines additional names for hard registers, thus allowing the asm option in declarations to refer to registers using alternate names. 
> ```
Is it possible to just not use magic numbers here at all? Do these correspond to something that is available in .td files? Is any of this possibly subject to change? Or if it is defined in some predefined macro/system header, etc. can we use the values from there?


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  https://reviews.llvm.org/D55192/new/

https://reviews.llvm.org/D55192